Electrically heated hose



March 3, 1942. MARICK 2,274,839

ELECTRI CALLY HEATED HOSE Filed May 21, 1941 1 N VENTOR.

ATTORNE Y Patented Mar. 3, 1 942 ELECTRICALLY HEATED HOSE Louis Marick,Grosse Pointe Farms, Mich assignor to United States Rubber Company, NewYork, N. Y., a corporation of New Jersey Application May 21, 1941,Serial No. 394,435

5 Claims.

This invention relates to electrically heated hose and more particularlyto electrically heated means embodied in a hose or tube to heat thesame.

It may be desirable from time to time to heat various gas or liquidfluids such as gases, oil, water, milk and solutions of inorganic andorganic chemicals. These fluids may be easily heated to a moderatelyhigh temperature by passing them through an electrically heated hosesuch as contemplated by the present invention.

Various types of hose may be provided with the electrically heated meansh'erein contemplated but the heating means is preferably embodied inhose having a sufliciently thick wall to permit the heating means to beconfined between the inner and outer walls of the hose where it will beprotected by the covering layers or other material forming the body ofthe hose.

The hose heating element comprises a strip of fabric or other sheetmaterial that is treated with an electrically conductive plastic suchfor example as rubber composition containing electrically conductivecarbon and having conductor wires secured along the side edges of thestrip;

so that when a diiferent electric potential is maintained between thesewires the current will now across the conductive strip from one wire tothe other and generate heat uniformly throughout the area of the strip.

The heating element herein contemplated may be wound helically about aninner layer of the hose structure throughout the length thereof and thena covering layer of the hose structure may be applied over such heatingelement In another construction the heating element may be arrangedlengthwise of the incompleted hose so that the heating wires extendparallel to the hose opening and the current conducting material extendspart way around the hose in the form of an are having as many degrees asdesired, whereupon the outer plies or other cover forming material maybe applied over such heating element to protect the same.

One end of each conductor wire should project from such hose so that thetwo wires may be connected to a suitable source of electric energy andthereby cause current to flow across the current conducting strip togenerate heat along the tube throughout the strip area.

The above and other features of the invention will be further understoodfrom the.following description when read in connection with theaccompanying drawing wherein:

Fig. 1 is a side elevation of a piece of hose embodying the features ofthe present invention and having the outer cover partially removed todisclose the electric heating element.

Fig. 2 is a side elevation of the hose of Fig. 1, the heating elementbeing shown in dotted lines within the hose wall.

Fig. 3 is a view similar to Fig. 1 showing a modified type of heatingelement extending lengthwise of and partly around the inner wallstructure of the hose; and

Fig. 4 is an enlarged sectional view taken on the line 4-4 of Fig. 3.

The present invention may be embodied in various types of hose such forexample as rubber hose, garden hose, hose formed of various types andnumbers of layers or plies as well-as hose formed of various plasticmaterials.

'In the embodiment of the invention illustrated in Figs. 1 and 2 of thedrawing, the hose is shown as provided with an inner wall structure Illand outer wall structure II and between these walls It and II isprovided the heating element which 'is shown as wound helically aboutthe tubular member III as indicated by the coils I2.

This heating element is preferably formed of a strip I! of woven fabricor other sheet material that is treated with an electrically conductiveplastic material such for example as rubber containing electricallyconductive carbon, to thereby render the strip capable of generatingheat when a diiferent ele'ttric potential is maintained between spacedportions thereof. The operating current is preferably supplied to thisstrip l3 by providing the conductor wires H and I5 secured along theside edges of the strip, preferably by folding the marginal side edgesof the strip around and in contact with the wires so as to form a goodelectrical contact therebetween. The adjacent edges of the helicallycoiled heated element should be spaced as shown so as to prevent theseedges containing wires of different potentials from contacting andforming a short circuit.

After the heating element l3, I4 and I5 is wound helically upon thetubular wall III as shown in Fig. 1 the covering wall ll may be applieddirectly over such heating element to conceal and protect the same, andif the walls l0 and II as well as the sheet it contain a substantialamount; of rubber the complete hose may be vulcanized to form a firmbond between the rubber of the strip l3 and the walls Ill and II. Thewires l4 and I5 preferably protrude at one end from the finished tube asshown in Fig. 2 so that they may be connected to any suitable source ofelectric energy such'as the ordinary household current or it desired toa current of considerably lower voltage, such for example as volts.

In the modified construction of Figs. 3 and 4 the hose is shown asprovided with an inner wall portion HI and outer wall portion II as inFigs. 1 and 2, but in this modified construction the heating element isnot wound helically about the inner wall ill but extends longitudinallythereof, and comprises a current conductive strip of sheet material l6similar to the strip I: of Fig. 1 and has its marginal edge portionssecured to the current supply wires l1 and It, as in Fig. 1. These wiresit will be noted extend lengthwise of the hose and the heating strip l6encircles as large a portion of the inner tube structure HI as desired,so that when a difierent electric potential is maintained between thewires I l and I8 current will fiow transversely of the strip l6 from onewire to the other to heat this strip and the hose in which it isembodied. If the portions III, II and ii of the hose are formed ofrubber or contain a substantial amount of rubber then they all may bevulcanized together.

The strip l3 or [6 is rendered electrically conductive by treating itwith a rubber cement or rubber dispersion or other plastic materialcontaining conductive carbon particles. One example of a good practicalelectrically conductive cement which may be used to coat the strip ll orI is as follows:

- Parts by weight Rubber 100.

The hose construction of the present invention has been designed moreparticularly to supply a moderate amount of heat, below the temperatureof boiling water, but a. higher temperature may be employed if the strip13 or ii is formed of non-combustible material such as woven asbestoswhich has been treated with conductive rubber and the other structure ofthe hose is capable of operating at such higher temperatures.

It will be apparent from the foregoing that a heating element such asherein contemplated may be embodied in various types of flexible hosewithout appreciably increasing its size or decreasing its flexibility,and that by placing such heating element in the interior of the hosestructure it will be concealed and protected from injury. The presenthose is well adapted for use in aircrafts to heat the oil lines but asabove stated may be employed to heat various fiuids.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. An electrically heated hose formed of a plurality of layers thatprovide an inner wall and outer wall, a heating element confined betweentwo of said layers along the hose, and consisting of a strip 01' sheetmaterial treated with electrically conductive rubber and having currentsupply wires secured along the side edges of the strip and adapted whena difierent electric potential is maintained between the wires to causecurrent to flow across said strip and heat the hose.

2. A rubber hose formed of a plurality of layers, a heating elementconfined between two of the layers, and consisting of a strip of sheetmaterial treated with electrically conductive plastic material andhaving current supply wires secured along the side edges of the stripand adapted when a different electric potential is maintained betweenthe wires to cause current to fiow across the strip and thereby heat thehose.

3. A rubber hose formed of rubber containing layers, a heating elementconfined between two of the layers, and consisting of a strip of sheetmaterial treated with electrically conductive rubber adapted to bevulcanized in place between said layers and provided with current supplywires secured along the side edges of the strip and adapted when adifferent electric potential is maintained between the wires to causecurrent to fiow across the strip and thereby heat the hose. 4. A hoseformed or a plurality of layers, a heating element wrapped helically ofthe hose between two or the layers, and consisting of a strip of sheetmaterial treated with electrically conductive plastic material andhaving current supply wires secured along the side edges 01' the stripand adapted when a diflerent electric potential is maintained betweenthe wires to cause current to fiow across the strip and thereby heat thehose. 5. A hose formed at least in part of plastic material and providedwith a heating element disposed between its inner and outer walls, saidelement consisting of a strip of sheet material treated withelectrically conductive plastic material and having current supply wiressecured along the side edges of the strip and adapted when a dififerentelectrical potential is maintained between the wires to cause current toflow across the strip and thereby heat the hose.

LOUIS MARICK.

